Rotor



April 8,1941. w. L. HANSEN ET AL 3 ROTOR Filed July 3, 1939 /NVENTO/?5 WILL/AM L. HANSEN IRA N HURST ATTOFPNEQS Patented Apr. 8, i941 accuser aoroa Wiliiam ill. Hansen and Era N. Hurst, Princeton, ind, assignors to Hansen Mfg. @ompany, Ina, frinceton, End, a corporation oil Indiana Application July 3, 1939, Serial No. 282,719

(ill. E iz -120) @laims.

This invention relates to electrical synchronous motors, and in particular, to rotors for such motors and processes or making such rotors.

One object of this invention is to provide a rotor for an electrical synchronous motor including a substantially cylindrical band of magnetic material having a plurality of incisions therein for providing pole pieces.

Another object is to provide such a rotor vwherein the incisions constitute substantially arcuate slots formed in the cylindricalband.

Another object is to provide a rotor comprising a shaft with a support thereon having a peripheral flange, and a cylindrical band of magnetic material disposed within said flange Figure 5' is a perspective view showing the 5 strip of Figure 4 provided with incisions to form upstanding tabs.

Figure 6 is a section along the line S in Figure 5.

Figure '7 is a view similar to Figure 5, but showing the finished band with the tabs bent back into alignment with the remainder of the strip.

Figure 8 is a section along the line l38 in Figure 7.

Figure 9 is an elevation of a ring of magnetic material from which the rotor may be made by a modified procedure.

Figure 10 is an enlarged view of a portion of the ring shown in Figure 9 with an incision made therein, and a tab struck upwardly therefrom.

Figure 11 is a view similar to Figures 9 and 10, but in a later stage of manufacture with the tabs bent backward into alignment with the remainder of the ring.

Figure 12 is a view of the finished rotor band with a portion of the ring of Figure 11 bent into cylindrical form.

Referring to the drawing in detail, Figure 1 shows the rotor of this invention as consisting of a shaft "I having a hub H with a web I 2 extending outwardly therefrom, and having a peripheral flange it. Mounted within the flange i3 is a rotor band it of substantially cylindrical form. This rotor band it is preferably of magnetic steel and may be formed either in a single piece or in the form of a strip which is sprung into the space within the flange i3, as hereinafter explained. The rotor band i4 is provided with circumferentially spaced incisions l5, which serve to interrupt the magnetic path and in this manner to provide pole pieces around the rotor band 58.

The rotor of Figure 1, generally designated it,

is shown in position upon a motor in Figures 2 and 3. This motor may be of any suitable type, the type shown being described and claimed in our copending application, Ser. No. 282,718, filed July 3, 1939. This motor consists of a magnetic core ll having reduced diameter portions 53 and :19, upon which are mounted outer and inner pole members 28 and 2 l, respectively. The outer pole member 28 is provided with axially extending pole pieces 22 and 23, which are alternately encircled by an undulating shading member 2d of non-magnetic metal, such as copper. The shading member 25 passes over the outer surfaces of the pole pieces 22 and their undulating portions 25 extend substantially around three sides of each pole piece 23, leaving the outer surface thereof exposed. In this manner the outer pole pieces 23 are shaded, whereas the outer pole pieces 22 are left unshaded.

The inner pole member 2E is provided with radiating pole pieces 26 and 21, the tips of which extend outward into close proximity to the tips of the outer pole pieces 22 and 23. The inner pole pieces 2? are shaded by a shading ring having undulating portions 29 passing around three sides of each inner pole piece 21, but passing over one surface only of each pole piece 26. In this manner the inner pole pieces 21 are shaded, whereas the inner pole pieces 26 are left unshaded. The shading ring 28 is likewise of non-magnetic metal, such as copper.

In order to energize the field structure thus described the core I1 is encircled by a grooved insulating member 29 having a field energizing winding 30 therein. The core I! is provided with a bore 3i with plugs 32 and 33 having coaxial bores 34 and 35 for rotatably supporting the rotor shaft ID. The rotor band II is then dis posed adjacent the tips of the outer and inner pole members 22, 23, 26 and 21. The incisions I: provide for pole areas in the rotor band I 4 so that the band has a variable magnetic reluctance.

The manufacture of rotor band it may be accomplished in two different ways. By the first process (Figures 4 to 8) a strip it of magnetic steel is punched with incisions it. During the punching process tabs 15 are struck up from the surface of the strip is, as shown in Figures 5 and 6. Subsequently, however, these tabs it are pushed or bent back into alignment with the remainder of the strip M, as shown in Figures 7 and 8. The strip may then be sprung into cylindrical shape and inserted within the flange 88, where it is held in place by its natural resilience.

In the second process of manufacture a ring 36 of magnetic steel is selected and provided with incisions l5, spaced circumferentially therearound by a punching process as shown in Figure 10. During the punching process tabs It are raised above the adjacent surface of the ring 36, as shown in Figure 10. Subsequently, however, these tabs i55 are bentfor pushed back into alignment with the remainder of the ring, as shown in Figure 11. The ring is then subjected to the action of mating dies so that the peripheral portion of the ring 85 is drawn into an axial cylindrical flange 237?. By this means the rotor band may he made in a single piece.

It will be understood that we desire to comprehend within our invention such modifications as come within the scope of the claims and the invention.

Having thus fully described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A rotor for synchronous motors comprising a shaft, a support mounted thereon, and a cyaasaeei lindrical band of magnetic material mounted on said support coaxial with said shaft, said band having spaced relatively narrowincisions therein, said incisions being of approximately ushaped form and having the legs oi the incisions extending along the direction of rotation of the rotor;

2. A rotor for synchronous motors comprising a shaft, a support mounted thereon, and a cylindrical band of magnetic material mounted on said support coaxial with said shaft, said band having spaced incisions therein, said incisions io U-shaped polar areas substantially in alent with the rinder of said band, the curved portion of each U-shaped area extending along the direction of rotation of the rotor.

3. A rotor for synchronous motors comprising a shaft, a support mounted on said shaft having a peripheral flange, and a cylindrical band of magnetic material mounted on said support within said flange, said band having spaced incisions therein of extremely relatively small width, the material immediately adjacent each incision being in alignment with the remainder of the hand.

a. A rotor for synchronous motors comprising a shaft, a support mounted on said shaft having a peripheral flange, anda cylindrical band of magnetic material mounted on said support with in said flange, said band having spaced relatively narrow incisions therein, said incisions being oi approximately U-shaped term with the legs of the incisions extending along the direction of rotation of the rotor.

'Ii' 5 YA L. HANSEN. IRA N. HURST. 

